1
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Gammond LVD, Zeidler A, Youngman RE, Fischer HE, Bull CL, Salmon PS. Transformations to the aluminum coordination environment and network polymerization in amorphous aluminosilicates under pressure. J Chem Phys 2024; 161:074503. [PMID: 39149989 DOI: 10.1063/5.0218574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Accepted: 07/26/2024] [Indexed: 08/17/2024] Open
Abstract
The structure of calcium aluminosilicate glasses (CaO)x(Al2O3)y(SiO2)1-x-y with the near tectosilicate compositions x ≃ 0.19 and 1 - x - y ≃ 0.61 or x ≃ 0.26 and 1 - x - y ≃ 0.49 was investigated by in situ high-pressure neutron diffraction and 27Al nuclear magnetic resonance (NMR) spectroscopy. The results show three distinct pressure regimes for the transformation of the aluminum coordination environment from tetrahedral to octahedral, which map onto the deformations observed in the production of permanently densified materials. The oxygen packing fraction serves as a marker for signaling a change to the coordination number of the network forming motifs. For a wide variety of permanently densified aluminosilicates, the aluminum speciation shares a common dependence on the reduced density ρ' = ρ/ρ0, where ρ is the density and ρ0 is its value for the uncompressed material. The observed increase in the Al-O coordination number with ρ' originates primarily from the formation of six-coordinated aluminum Al(VI) species, the fraction of which increases rapidly beyond a threshold ρthr'∼ 1.1. The findings are combined to produce a self-consistent model for pressure-induced structural change. Provided the glass network is depolymerized, one-coordinated non-bridging oxygen atoms are consumed to produce two-coordinated bridging oxygen atoms, thus increasing the network connectivity in accordance with the results from 17O NMR experiments. Otherwise, three-coordinated oxygen atoms or triclusters appear, and their fraction is quantified by reference to the mean coordination number of the silicon plus aluminum species. The impact of treating Al(VI) as a network modifier is discussed.
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Affiliation(s)
| | - Anita Zeidler
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | - Randall E Youngman
- Science and Technology Division, Corning Incorporated, Corning, New York 14831, USA
| | - Henry E Fischer
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Craig L Bull
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Philip S Salmon
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
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2
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Chen W, Wei S, Wang W. Subslab ultra low velocity anomaly uncovered by and facilitating the largest deep earthquake. Nat Commun 2024; 15:2754. [PMID: 38553481 PMCID: PMC10980710 DOI: 10.1038/s41467-024-47129-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 03/21/2024] [Indexed: 04/02/2024] Open
Abstract
It is enigmatic that M8+ earthquakes can take place at depth greater than 600 km inside the slab, where the P-T conditions generally do not favor seismic slip rate (~m/s) on faults. Here we provide fresh insights to the initial rupture and mechanism of the Mw 8.3 Sea of Okhotsk earthquake by analyzing high-frequency (up to 0.8 Hz) teleseismic array data. We determine the relative location and timing of two early subevents, and the geometry and velocity perturbation of a nearby structure anomaly. We found a small-scale (~30 × 60 × 60 km) ultralow (-18 ± 2%) P-wave velocity anomaly located beneath the Pacific slab around the 660 km discontinuity. The volatile-bearing highly melted nature of the anomaly provides significant buoyancy, stressing the slab dramatically closer to the critical condition for thermal runaway weakening that allows the rupture to propagate beyond the metastable olivine wedge, forming M8+ events. Enormous velocity reduction urges for further mineral physics and geodynamic investigations.
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Affiliation(s)
- Weiwen Chen
- Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore
- Institute of Geophysics, China Earthquake Administration, Beijing, China
| | - Shengji Wei
- Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore.
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore.
- Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
| | - Weitao Wang
- Institute of Geophysics, China Earthquake Administration, Beijing, China.
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3
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Hong X, Newville M, Ding Y. Local structural investigation of non-crystalline materials at high pressure: the case of GeO 2glass. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:164001. [PMID: 36764002 DOI: 10.1088/1361-648x/acbb4c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
Local structures play a crucial role in the structural polyamorphism and novel electronic properties of amorphous materials, but their accurate measurement at high pressure remains a formidable challenge. In this article, we use the local structure of network-forming GeO2glass as an example, to present our recent approaches and advances in high-energy x-ray diffraction, high-pressure x-ray absorption fine structure, andab initiofirst-principles density functional theory calculations and simulations. Although GeO2glass is one of the best studied materials in the field of high pressure research due to its importance in glass theory and geophysical significance, there are still some long-standing puzzles, such as the existence of appreciable distinct fivefold[5]Ge coordination at low pressure and the sixfold-plus[6+]Ge coordination at ultrahigh pressure. Our work sheds light on the origin of pressure-induced polyamorphism of GeO2glass, and the[5]Ge polyhedral units may be the dominant species in the densification mechanism of network-forming glasses from tetrahedral to octahedral amorphous structures.
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Affiliation(s)
- Xinguo Hong
- Center for High Pressure Science and Technology Advanced Research, Beijing 100193, People's Republic of China
| | - Matt Newville
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, United States of America
| | - Yang Ding
- Center for High Pressure Science and Technology Advanced Research, Beijing 100193, People's Republic of China
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4
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Bajgain SK, Ashley AW, Mookherjee M, Ghosh DB, Karki BB. Insights into magma ocean dynamics from the transport properties of basaltic melt. Nat Commun 2022; 13:7590. [PMID: 36481757 PMCID: PMC9731987 DOI: 10.1038/s41467-022-35171-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 11/17/2022] [Indexed: 12/13/2022] Open
Abstract
The viscosity of magma plays a crucial role in the dynamics of the Earth: from the crystallization of a magma ocean during its initial stages to modern-day volcanic processes. However, the pressure-dependence behavior of viscosity at high pressure remains controversial. In this study, we report the results of first-principles molecular dynamics simulations of basaltic melt to show that the melt viscosity increases upon compression along each isotherm for the entire lower mantle after showing minima at ~6 GPa. However, elevated temperatures of the magma ocean translate to a narrow range of viscosity, i.e., 0.01-0.03 Pa.s. This low viscosity implies that the crystallization of the magma ocean could be complete within a few million years. These results also suggest that the crystallization of the magma ocean is likely to be fractional, thus supporting the hypothesis that present-day mantle heterogeneities could have been generated during the early crystallization of the primitive mantle.
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Affiliation(s)
- Suraj K Bajgain
- Earth Materials Laboratory, Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, USA.
- Department of Geology, School of Natural Resources & Environment, Lake Superior State University, Sault Ste Marie, MI, USA.
| | - Aaron Wolfgang Ashley
- Earth Materials Laboratory, Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, USA
| | - Mainak Mookherjee
- Earth Materials Laboratory, Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, USA.
| | - Dipta B Ghosh
- School of Electrical Engineering and Computer Science, Department of Geology and Geophysics, Center for Computation and Technology, Louisiana State University, Baton Rouge, LA, USA
| | - Bijaya B Karki
- School of Electrical Engineering and Computer Science, Department of Geology and Geophysics, Center for Computation and Technology, Louisiana State University, Baton Rouge, LA, USA.
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5
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Sun N, Mao Z, Zhang X, Tkachev SN, Lin JF. Hot dense silica glass with ultrahigh elastic moduli. Sci Rep 2022; 12:13946. [PMID: 35977985 PMCID: PMC9385850 DOI: 10.1038/s41598-022-18062-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 08/04/2022] [Indexed: 11/25/2022] Open
Abstract
Silicate and oxide glasses are often chemically doped with a variety of cations to tune for desirable properties in technological applications, but their performances are often limited by relatively lower mechanical and elastic properties. Finding a new route to synthesize silica-based glasses with high elastic and mechanical properties needs to be explored. Here, we report a dense SiO2-glass with ultra-high elastic moduli using sound velocity measurements by Brillouin scattering up to 72 GPa at 300 K. High-temperature measurements were performed up to 63 GPa at 750 K and 59 GPa at 1000 K. Compared to compression at 300 K, elevated temperature helps compressed SiO2-glass effectively overcome the kinetic barrier to undergo permanent densification with enhanced coordination number and connectivity. This hot compressed SiO2-glass exhibits a substantially high bulk modulus of 361–429 GPa which is at least 2–3 times greater than the metallic, oxide, and silicate glasses at ambient conditions. Its Poisson’s ratio, an indicator for the packing efficiency, is comparable to the metallic glasses. Even after temperature quench and decompression to ambient conditions, the SiO2-glass retains some of its unique properties at compression and possesses a Poisson’s ratio of 0.248(11). In addition to chemical alternatives in glass syntheses, coupled compression and heating treatments can be an effective means to enhance mechanical and elastic properties in high-performance glasses.
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Affiliation(s)
- Ningyu Sun
- Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China.,CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, Anhui, 230026, China.,Frontiers Science Center for Planetary Exploration and Emerging Technologies, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Zhu Mao
- Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China. .,CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, Anhui, 230026, China. .,Frontiers Science Center for Planetary Exploration and Emerging Technologies, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| | - Xinyue Zhang
- Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Sergey N Tkachev
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL, 60637, USA
| | - Jung-Fu Lin
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, 78712, USA
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6
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Lobanov SS, Speziale S, Winkler B, Milman V, Refson K, Schifferle L. Electronic, Structural, and Mechanical Properties of SiO_{2} Glass at High Pressure Inferred from its Refractive Index. PHYSICAL REVIEW LETTERS 2022; 128:077403. [PMID: 35244414 DOI: 10.1103/physrevlett.128.077403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 11/29/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
We report the first direct measurements of the refractive index of silica glass up to 145 GPa that allowed quantifying its density, bulk modulus, Lorenz-Lorentz polarizability, and band gap. These properties show two major anomalies at ∼10 and ∼40 GPa. The anomaly at ∼10 GPa signals the onset of the increase in Si coordination, and the anomaly at ∼40 GPa corresponds to a nearly complete vanishing of fourfold Si. More generally, we show that the compressibility and density of noncrystalline solids can be accurately measured in simple optical experiments up to at least 110 GPa.
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Affiliation(s)
- Sergey S Lobanov
- Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany
- Institut für Geowissenschaften, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Golm 14476, Germany
| | - Sergio Speziale
- Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany
| | - Björn Winkler
- Institut für Geowissenschaften, Goethe-Universität Frankfurt, Altenhöferallee 1, 60438 Frankfurt am Main, Germany
| | - Victor Milman
- Dassault Systèmes BIOVIA, 334 Science Park, Cambridge CB4 0WN, United Kingdom
| | - Keith Refson
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Lukas Schifferle
- Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany
- Institut für Geowissenschaften, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Golm 14476, Germany
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7
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Konôpková Z, Morgenroth W, Husband R, Giordano N, Pakhomova A, Gutowski O, Wendt M, Glazyrin K, Ehnes A, Delitz JT, Goncharov AF, Prakapenka VB, Liermann HP. Laser heating system at the Extreme Conditions Beamline, P02.2, PETRA III. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1747-1757. [PMID: 34738928 PMCID: PMC8570206 DOI: 10.1107/s1600577521009231] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
A laser heating system for samples confined in diamond anvil cells paired with in situ X-ray diffraction measurements at the Extreme Conditions Beamline of PETRA III is presented. The system features two independent laser configurations (on-axis and off-axis of the X-ray path) allowing for a broad range of experiments using different designs of diamond anvil cells. The power of the continuous laser source can be modulated for use in various pulsed laser heating or flash heating applications. An example of such an application is illustrated here on the melting curve of iron at megabar pressures. The optical path of the spectroradiometry measurements is simulated with ray-tracing methods in order to assess the level of present aberrations in the system and the results are compared with other systems, that are using simpler lens optics. Based on the ray-tracing the choice of the first achromatic lens and other aspects for accurate temperature measurements are evaluated.
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Affiliation(s)
- Zuzana Konôpková
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
- European XFEL GmbH, Holzkoppel 4, Schenefeld, Germany
| | - Wolfgang Morgenroth
- Institut für Geowissenschaften, Kristallographie/Mineralogie, Goethe Universität Frankfurt am Main, Altenhöferallee 1, D-60438 Frankfurt am Main, Germany
| | - Rachel Husband
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Nico Giordano
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Anna Pakhomova
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Olof Gutowski
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Mario Wendt
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Konstantin Glazyrin
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Anita Ehnes
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | | | - Alexander F. Goncharov
- Earth and Planets Laboratory, Carnegie Institution for Science, 5251 Broad Branch Rd NW, Washington, DC 20015, USA
| | - Vitali B. Prakapenka
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, USA
| | - Hanns-Peter Liermann
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
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8
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Drewitt JWE. Liquid structure under extreme conditions: high-pressure x-ray diffraction studies. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:503004. [PMID: 34544063 DOI: 10.1088/1361-648x/ac2865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
Under extreme conditions of high pressure and temperature, liquids can undergo substantial structural transformations as their atoms rearrange to minimise energy within a more confined volume. Understanding the structural response of liquids under extreme conditions is important across a variety of disciplines, from fundamental physics and exotic chemistry to materials and planetary science.In situexperiments and atomistic simulations can provide crucial insight into the nature of liquid-liquid phase transitions and the complex phase diagrams and melting relations of high-pressure materials. Structural changes in natural magmas at the high-pressures experienced in deep planetary interiors can have a profound impact on their physical properties, knowledge of which is important to inform geochemical models of magmatic processes. Generating the extreme conditions required to melt samples at high-pressure, whilst simultaneously measuring their liquid structure, is a considerable challenge. The measurement, analysis, and interpretation of structural data is further complicated by the inherent disordered nature of liquids at the atomic-scale. However, recent advances in high-pressure technology mean that liquid diffraction measurements are becoming more routinely feasible at synchrotron facilities around the world. This topical review examines methods for high pressure synchrotron x-ray diffraction of liquids and the wide variety of systems which have been studied by them, from simple liquid metals and their remarkable complex behaviour at high-pressure, to molecular-polymeric liquid-liquid transitions in pnicogen and chalcogen liquids, and density-driven structural transformations in water and silicate melts.
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Affiliation(s)
- James W E Drewitt
- School of Physics, University of Bristol, H H Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
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9
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Solomatova NV, Caracas R. Buoyancy and Structure of Volatile-Rich Silicate Melts. JOURNAL OF GEOPHYSICAL RESEARCH. SOLID EARTH 2021; 126:e2020JB021045. [PMID: 33680690 PMCID: PMC7900987 DOI: 10.1029/2020jb021045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 12/17/2020] [Accepted: 12/20/2020] [Indexed: 06/12/2023]
Abstract
The early Earth was marked by at least one global magma ocean. Melt buoyancy played a major role for its evolution. Here we model the composition of the magma ocean using a six-component pyrolite melt, to which we add volatiles in the form of carbon as molecular CO or CO2 and hydrogen as molecular H2O or through substitution for magnesium. We compute the density relations from first-principles molecular dynamics simulations. We find that the addition of volatiles renders all the melts more buoyant compared to the reference volatile-free pyrolite. The effect is pressure dependent, largest at the surface, decreasing to about 20 GPa, and remaining roughly constant to 135 GPa. The increased buoyancy would have enhanced convection and turbulence, and thus promoted the chemical exchanges of the magma ocean with the early atmosphere. We determine the partial molar volume of both H2O and CO2 throughout the magma ocean conditions. We find a pronounced dependence with temperature at low pressures, whereas at megabar pressures the partial molar volumes are independent of temperature. At all pressures, the polymerization of the silicate melt is strongly affected by the amount of oxygen added to the system while being only weakly affected by the specific type of volatile added.
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Affiliation(s)
- Natalia V. Solomatova
- CNRSEcole Normale Supérieure de LyonLaboratoire de Géologie de Lyon LGLTPE UMR5276Centre Blaise PascalLyonFrance
| | - Razvan Caracas
- CNRSEcole Normale Supérieure de LyonLaboratoire de Géologie de Lyon LGLTPE UMR5276Centre Blaise PascalLyonFrance
- The Center for Earth Evolution and Dynamics (CEED)University of OsloOsloNorway
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10
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Kono Y, Shu Y, Kenney-Benson C, Wang Y, Shen G. Structural Evolution of SiO_{2} Glass with Si Coordination Number Greater than 6. PHYSICAL REVIEW LETTERS 2020; 125:205701. [PMID: 33258638 DOI: 10.1103/physrevlett.125.205701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/11/2020] [Indexed: 06/12/2023]
Abstract
Pair distribution function measurement of SiO_{2} glass up to 120 GPa reveals changes in the first-, second-, and third-neighbor distances associated with an increase in Si coordination number C_{Si} to >6 above 95 GPa. Packing fractions of Si and O determined from the first- and second-neighbor distances show marked changes accompanied with the structural evolution from C_{Si}=6 to >6. Structural constraints in terms of ionic radius ratio of Si and O, and ratio of nonbonded radius to bonded Si─O distance support the structural evolution of SiO_{2} glass with C_{Si}>6 at high pressures.
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Affiliation(s)
- Yoshio Kono
- Geophysical Laboratory, Carnegie Institution of Washington, 9700 South Cass Avenue, Argonne, Illinois 60439, USA
- Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan
| | - Yu Shu
- High Pressure Collaborative Access Team, X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Curtis Kenney-Benson
- High Pressure Collaborative Access Team, X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yanbin Wang
- GeoSoilEnviroCARS, Center for Advanced Radiation Sources, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - Guoyin Shen
- High Pressure Collaborative Access Team, X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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11
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Structural dynamics of basaltic melt at mantle conditions with implications for magma oceans and superplumes. Nat Commun 2020; 11:4815. [PMID: 32968073 PMCID: PMC7511909 DOI: 10.1038/s41467-020-18660-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 08/28/2020] [Indexed: 12/04/2022] Open
Abstract
Transport properties like diffusivity and viscosity of melts dictated the evolution of the Earth’s early magma oceans. We report the structure, density, diffusivity, electrical conductivity and viscosity of a model basaltic (Ca11Mg7Al8Si22O74) melt from first-principles molecular dynamics calculations at temperatures of 2200 K (0 to 82 GPa) and 3000 K (40–70 GPa). A key finding is that, although the density and coordination numbers around Si and Al increase with pressure, the Si–O and Al–O bonds become more ionic and weaker. The temporal atomic interactions at high pressure are fluxional and fragile, making the atoms more mobile and reversing the trend in transport properties at pressures near 50 GPa. The reversed melt viscosity under lower mantle conditions allows new constraints on the timescales of the early Earth’s magma oceans and also provides the first tantalizing explanation for the horizontal deflections of superplumes at ~1000 km below the Earth’s surface. Transport properties of melts in the deep Earth have dictated the evolution of the early Earth’s magma oceans and also govern many modern dynamic processes, such as plate tectonics. Here, the authors find there is a reversal in the trends of transport properties of basaltic melts at pressures near 50 GPa, with implications for the timescales of early Earth’s magma oceans.
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12
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A Practical Review of the Laser-Heated Diamond Anvil Cell for University Laboratories and Synchrotron Applications. CRYSTALS 2020. [DOI: 10.3390/cryst10060459] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the past couple of decades, the laser-heated diamond anvil cell (combined with in situ techniques) has become an extensively used tool for studying pressure-temperature-induced evolution of various physical (and chemical) properties of materials. In this review, the general challenges associated with the use of the laser-heated diamond anvil cells are discussed together with the recent progress in the use of this tool combined with synchrotron X-ray diffraction and absorption spectroscopy.
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13
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Kuwayama Y, Morard G, Nakajima Y, Hirose K, Baron AQR, Kawaguchi SI, Tsuchiya T, Ishikawa D, Hirao N, Ohishi Y. Equation of State of Liquid Iron under Extreme Conditions. PHYSICAL REVIEW LETTERS 2020; 124:165701. [PMID: 32383924 DOI: 10.1103/physrevlett.124.165701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 03/10/2020] [Indexed: 06/11/2023]
Abstract
The density of liquid iron has been determined up to 116 GPa and 4350 K via static compression experiments following an innovative analysis of diffuse scattering from liquid. The longitudinal sound velocity was also obtained to 45 GPa and 2700 K based on inelastic x-ray scattering measurements. Combining these results with previous shock-wave data, we determine a thermal equation of state for liquid iron. It indicates that Earth's outer core exhibits 7.5%-7.6% density deficit, 3.7%-4.4% velocity excess, and an almost identical adiabatic bulk modulus, with respect to liquid iron.
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Affiliation(s)
- Yasuhiro Kuwayama
- Department of Earth and Planetary Science, The University of Tokyo, 113-0033 Tokyo, Japan
- Geodynamics Research Center, Ehime University, 790-8577 Ehime, Japan
| | - Guillaume Morard
- Sorbonne Université, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Museum National d'Histoire Naturelle, UMR CNRS, 7590 Paris, France
- Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France
| | - Yoichi Nakajima
- Department of Physics, Kumamoto University, 860-8555 Kumamoto, Japan
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, 679-5148 Hyogo, Japan
| | - Kei Hirose
- Department of Earth and Planetary Science, The University of Tokyo, 113-0033 Tokyo, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, 152-8550 Tokyo, Japan
| | - Alfred Q R Baron
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, 679-5148 Hyogo, Japan
| | - Saori I Kawaguchi
- SPring-8, Japan Synchrotron Radiation Research Institute, 679-5198 Hyogo, Japan
| | - Taku Tsuchiya
- Geodynamics Research Center, Ehime University, 790-8577 Ehime, Japan
| | - Daisuke Ishikawa
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, 679-5148 Hyogo, Japan
- SPring-8, Japan Synchrotron Radiation Research Institute, 679-5198 Hyogo, Japan
| | - Naohisa Hirao
- SPring-8, Japan Synchrotron Radiation Research Institute, 679-5198 Hyogo, Japan
| | - Yasuo Ohishi
- SPring-8, Japan Synchrotron Radiation Research Institute, 679-5198 Hyogo, Japan
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14
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Drewitt JWE, Turci F, Heinen BJ, Macleod SG, Qin F, Kleppe AK, Lord OT. Structural Ordering in Liquid Gallium under Extreme Conditions. PHYSICAL REVIEW LETTERS 2020; 124:145501. [PMID: 32338984 DOI: 10.1103/physrevlett.124.145501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
The atomic-scale structure, melting curve, and equation of state of liquid gallium has been measured to high pressure (p) and high temperature (T) up to 26 GPa and 900 K by in situ synchrotron x-ray diffraction. Ab initio molecular dynamics simulations up to 33.4 GPa and 1000 K are in excellent agreement with the experimental measurements, providing detailed insight at the level of pair distribution functions. The results reveal an absence of dimeric bonding in the liquid state and a continuous increase in average coordination number n[over ¯]_{Ga}^{Ga} from 10.4(2) at 0.1 GPa approaching ∼12 by 25 GPa. Topological cluster analysis of the simulation trajectories finds increasing fractions of fivefold symmetric and crystalline motifs at high p-T. Although the liquid progressively resembles a hard-sphere structure towards the melting curve, the deviation from this simple description remains large (≥40%) across all p-T space, with specific motifs of different geometries strongly correlating with low local two-body excess entropy at high p-T.
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Affiliation(s)
- James W E Drewitt
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
| | - Francesco Turci
- H H Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Benedict J Heinen
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
| | - Simon G Macleod
- Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR, United Kingdom
- SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - Fei Qin
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
| | - Annette K Kleppe
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Chilton OX11 0DE, United Kingdom
| | - Oliver T Lord
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
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15
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Louvel M, Drewitt JWE, Ross A, Thwaites R, Heinen BJ, Keeble DS, Beavers CM, Walter MJ, Anzellini S. The HXD95: a modified Bassett-type hydrothermal diamond-anvil cell for in situ XRD experiments up to 5 GPa and 1300 K. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:529-537. [PMID: 32153294 PMCID: PMC7064104 DOI: 10.1107/s1600577519016801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/16/2019] [Indexed: 05/10/2023]
Abstract
A new diamond-anvil cell apparatus for in situ synchrotron X-ray diffraction measurements of liquids and glasses, at pressures from ambient to 5 GPa and temperatures from ambient to 1300 K, is reported. This portable setup enables in situ monitoring of the melting of complex compounds and the determination of the structure and properties of melts under moderately high pressure and high temperature conditions relevant to industrial processes and magmatic processes in the Earth's crust and shallow mantle. The device was constructed according to a modified Bassett-type hydrothermal diamond-anvil cell design with a large angular opening (θ = 95°). This paper reports the successful application of this device to record in situ synchrotron X-ray diffraction of liquid Ga and synthetic PbSiO3 glass to 1100 K and 3 GPa.
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Affiliation(s)
- Marion Louvel
- School of Earth Science, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK
- Institute for Mineralogy, WWU, D-48149 Munster, Germany
| | - James W. E. Drewitt
- School of Earth Science, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK
| | - Allan Ross
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Diamond House, Didcot OX11 0DE, UK
| | - Richard Thwaites
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Diamond House, Didcot OX11 0DE, UK
| | - Benedict J. Heinen
- School of Earth Science, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK
| | - Dean S. Keeble
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Diamond House, Didcot OX11 0DE, UK
| | - Christine M. Beavers
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Diamond House, Didcot OX11 0DE, UK
| | - Michael J. Walter
- Geophysical Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road NW, Washington, DC 20015, USA
| | - Simone Anzellini
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Diamond House, Didcot OX11 0DE, UK
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16
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Solomatova N, Caracas R. Pressure-Induced Coordination Changes in a Pyrolitic Silicate Melt From Ab Initio Molecular Dynamics Simulations. JOURNAL OF GEOPHYSICAL RESEARCH. SOLID EARTH 2019; 124:11232-11250. [PMID: 32025456 PMCID: PMC6988478 DOI: 10.1029/2019jb018238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/04/2019] [Accepted: 10/29/2019] [Indexed: 06/10/2023]
Abstract
With ab initio molecular dynamics simulations on a Na-, Ca-, Fe-, Mg-, and Al-bearing silicate melt of pyrolite composition, we examine the detailed changes in elemental coordination as a function of pressure and temperature. We consider the average coordination as well as the proportion and distribution of coordination environments at pressures and temperatures encompassing the conditions at which molten silicates may exist in present-day Earth and those of the Early Earth's magma ocean. At ambient pressure and 2,000 K, we find that the average coordination of cations with respect to oxygen is 4.0 for Si-O, 4.0 for Al-O, 3.7 for Fe-O, 4.6 for Mg-O, 5.9 for Na-O, and 6.2 for Ca-O. Although the coordination for iron with respect to oxygen may be underestimated, the coordination number for all other cations are consistent with experiments. By 15 GPa (2,000 K), the average coordination for Si-O remains at 4.0 but increases to 4.1 for Al-O, 4.2 for Fe-O, 4.9 for Mg-O, 8.0 for Na-O, and 6.8 for Ca-O. The coordination environment for Na-O remains approximately constant up to core-mantle boundary conditions (135 GPa and 4000 K) but increases to about 6 for Si-O, 6.5 for Al-O, 6.5 for Fe-O, 8 for Mg-O, and 9.5 for Ca-O. We discuss our results in the context of the metal-silicate partitioning behavior of siderophile elements and the viscosity changes of silicate melts at upper mantle conditions. Our results have implications for melt properties, such as viscosity, transport coefficients, thermal conductivities, and electrical conductivities, and will help interpret experimental results on silicate glasses.
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Affiliation(s)
- N.V. Solomatova
- CNRS, École Normale Supérieure de LyonLaboratoire de Géologie de Lyon, CNRS UMR 5276LyonFrance
| | - R. Caracas
- CNRS, École Normale Supérieure de LyonLaboratoire de Géologie de Lyon, CNRS UMR 5276LyonFrance
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17
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CO 3+1 network formation in ultra-high pressure carbonate liquids. Sci Rep 2019; 9:15416. [PMID: 31659181 PMCID: PMC6817860 DOI: 10.1038/s41598-019-51306-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 09/24/2019] [Indexed: 11/09/2022] Open
Abstract
Carbonate liquids are an important class of molten salts, not just for industrial applications, but also in geological processes. Carbonates are generally expected to be simple liquids, in terms of ionic interactions between the molecular carbonate anions and metal cations, and therefore relatively structureless compared to more “polymerized” silicate melts. But there is increasing evidence from phase relations, metal solubility, glass spectroscopy and simulations to suggest the emergence of carbonate “networks” at length scales longer than the component molecular anions. The stability of these emergent structures are known to be sensitive to temperature, but are also predicted to be favoured by pressure. This is important as a recent study suggests that subducted surface carbonate may melt near the Earth’s transition zone (~44 km), representing a barrier to the deep carbon cycle depending on the buoyancy and viscosity of these liquids. In this study we demonstrate a major advance in our understanding of carbonate liquids by combining simulations and high pressure measurements on a carbonate glass, (K2CO3-MgCO3) to pressures in excess of 40 GPa, far higher than any previous in situ study. We show the clear formation of extended low-dimensional carbonate networks of close CO32− pairs and the emergence of a “three plus one” local coordination environment, producing an unexpected increase in viscosity with pressure. Although carbonate melts may still be buoyant in the lower mantle, an increased viscosity by at least three orders of magnitude will restrict the upward mobility, possibly resulting in entrainment by the down-going slab.
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18
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Petitgirard S, Jacobs J, Cerantola V, Collings IE, Tucoulou R, Dubrovinsky L, Sahle CJ. A versatile diamond anvil cell for X-ray inelastic, diffraction and imaging studies at synchrotron facilities. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:095107. [PMID: 31575253 DOI: 10.1063/1.5119025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/25/2019] [Indexed: 06/10/2023]
Abstract
We present a new diamond anvil cell design, hereafter called mBX110, that combines both the advantages of a membrane and screws to generate high pressure. It enables studies at large-scale facilities for many synchrotron X-ray techniques and has the possibility to remotely control the pressure with the membrane as well as the use of the screws in the laboratory. It is fully compatible with various gas-loading systems as well as high/low temperature environments in the lab or at large scale facilities. The mBX110 possesses an opening angle of 85° suitable for single-crystal diffraction or Brillouin spectroscopy and a large side opening of 110° which can be used for X-ray inelastic techniques, such as X-ray Raman scattering spectroscopy, but also for X-ray emission, X-ray fluorescence, or X-ray absorption. An even larger opening of 150° can be manufactured enabling X-ray imaging tomography. We report data obtained with the mBX110 on different beamlines with single-crystal diffraction of stishovite up to 55 GPa, X-ray powder diffraction of rutile-GeO2 and tungsten to 25 GPa and 280 GPa, respectively, X-Ray Raman spectra of the Si L-edge in silica to 95 GPa, and Fe Kβ X-ray emission spectra on a basalt glass to 17 GPa.
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Affiliation(s)
| | - Jeroen Jacobs
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble 38000, France
| | - Valerio Cerantola
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble 38000, France
| | - Ines E Collings
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble 38000, France
| | - Remi Tucoulou
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble 38000, France
| | - Leonid Dubrovinsky
- Bayerisches Geoinstitut, University of Bayreuth, Bayreuth D-95490, Germany
| | - Christoph J Sahle
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble 38000, France
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19
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Shi R, Tanaka H. Distinct signature of local tetrahedral ordering in the scattering function of covalent liquids and glasses. SCIENCE ADVANCES 2019; 5:eaav3194. [PMID: 30838331 PMCID: PMC6397023 DOI: 10.1126/sciadv.aav3194] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/16/2019] [Indexed: 05/19/2023]
Abstract
Tetrahedral amorphous materials such as SiO2, GeO2, Si, Ge, C, and chalcogenides are extremely important in nature and technology. It is known that covalent bonding favors local tetrahedral order in these materials. However, how to extract information on this structural order from the scattering function has remained elusive. By analyzing the structure of simulated SiO2 and experimental data of various tetrahedral materials, we show that the lowest wave number peak, known as the first sharp diffraction peak (FSDP), and a few higher wave number ones in the scattering functions come from the characteristic density waves of a single tetrahedral unit. FSDP is thus a direct measure of the tetrahedrality. This finding opens the door for long-awaited experimental access to the characterization of disordered amorphous structures.
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20
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Bykova E, Bykov M, Černok A, Tidholm J, Simak SI, Hellman O, Belov MP, Abrikosov IA, Liermann HP, Hanfland M, Prakapenka VB, Prescher C, Dubrovinskaia N, Dubrovinsky L. Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts. Nat Commun 2018; 9:4789. [PMID: 30442940 PMCID: PMC6237875 DOI: 10.1038/s41467-018-07265-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 10/19/2018] [Indexed: 11/24/2022] Open
Abstract
Modelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO2) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations. Their crystal structures are drastically different from any previously considered models, but explain well features of pair-distribution functions of highly densified silica glass and molten basalt at high pressure. Built of four, five-, and six-coordinated silicon, coesite-IV and coesite-V contain SiO6 octahedra, which, at odds with 3rd Pauling's rule, are connected through common faces. Our results suggest that possible silicate liquids in Earth's lower mantle may have complex structures making them more compressible than previously supposed.
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Affiliation(s)
- E Bykova
- Photon Sciences, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607, Hamburg, Germany.
- Bayerisches Geoinstitut, University of Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany.
| | - M Bykov
- Bayerisches Geoinstitut, University of Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany
- Materials Modeling and Development Laboratory, National University of Science and Technology 'MISIS', Leninsky Avenue 4, 119049, Moscow, Russia
| | - A Černok
- Bayerisches Geoinstitut, University of Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany
- School of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
| | - J Tidholm
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - S I Simak
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - O Hellman
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
- Department of Applied Physics and Materials Science, California Institute of Technology, 1200 East California Boulevard, Pasadena, California, 91125, USA
| | - M P Belov
- Materials Modeling and Development Laboratory, National University of Science and Technology 'MISIS', Leninsky Avenue 4, 119049, Moscow, Russia
| | - I A Abrikosov
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - H-P Liermann
- Photon Sciences, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607, Hamburg, Germany
| | - M Hanfland
- European Synchrotron Radiation Facility (ESRF), 6 Rue Jules Horowitz, 38000, Grenoble, France
| | - V B Prakapenka
- Center for Advanced Radiation Sources, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois, 60637, USA
| | - C Prescher
- Center for Advanced Radiation Sources, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois, 60637, USA
- Institute of Geology and Mineralogy, Universität zu Köln, Zülpicher Straße 49b, 50674, Köln, Germany
| | - N Dubrovinskaia
- Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany
| | - L Dubrovinsky
- Bayerisches Geoinstitut, University of Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany
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21
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Local structure of molten AuGa 2 under pressure: Evidence for coordination change and planetary implications. Sci Rep 2018; 8:6844. [PMID: 29717192 PMCID: PMC5931613 DOI: 10.1038/s41598-018-25297-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/23/2018] [Indexed: 11/08/2022] Open
Abstract
In situ x-ray diffraction measurements and inverse Monte Carlo simulations of pair distribution functions were used to characterize the local structure of molten AuGa2 up to 16 GPa and 940 K. Our results document systematic changes in liquid structure due to a combination of bond compression and coordination increase. Empirical potential structure refinement shows the first-neighbor coordination of Ga around Au and of Au around Ga to increase from about 8 to 10 and 4 to 5, respectively between 0 and 16 GPa, and the inferred changes in liquid structure can explain the observed melting-point depression of AuGa2 up to 5 GPa. As intermetallic AuGa2 is an analogue for metallic SiO2 at much higher pressures, our results imply that structural changes documented for non-metallic silicate melts below 100 GPa are followed by additional coordination changes in the metallic state at pressures in the 0.2–1 TPa range achieved inside large planets.
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22
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Pressure-induced structural change in MgSiO 3 glass at pressures near the Earth's core-mantle boundary. Proc Natl Acad Sci U S A 2018; 115:1742-1747. [PMID: 29432162 DOI: 10.1073/pnas.1716748115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Knowledge of the structure and properties of silicate magma under extreme pressure plays an important role in understanding the nature and evolution of Earth's deep interior. Here we report the structure of MgSiO3 glass, considered an analog of silicate melts, up to 111 GPa. The first (r1) and second (r2) neighbor distances in the pair distribution function change rapidly, with r1 increasing and r2 decreasing with pressure. At 53-62 GPa, the observed r1 and r2 distances are similar to the Si-O and Si-Si distances, respectively, of crystalline MgSiO3 akimotoite with edge-sharing SiO6 structural motifs. Above 62 GPa, r1 decreases, and r2 remains constant, with increasing pressure until 88 GPa. Above this pressure, r1 remains more or less constant, and r2 begins decreasing again. These observations suggest an ultrahigh-pressure structural change around 88 GPa. The structure above 88 GPa is interpreted as having the closest edge-shared SiO6 structural motifs similar to those of the crystalline postperovskite, with densely packed oxygen atoms. The pressure of the structural change is broadly consistent with or slightly lower than that of the bridgmanite-to-postperovskite transition in crystalline MgSiO3 These results suggest that a structural change may occur in MgSiO3 melt under pressure conditions corresponding to the deep lower mantle.
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23
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Clark AN, Lesher CE. Elastic properties of silicate melts: Implications for low velocity zones at the lithosphere-asthenosphere boundary. SCIENCE ADVANCES 2017; 3:e1701312. [PMID: 29255800 PMCID: PMC5733110 DOI: 10.1126/sciadv.1701312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
Low seismic velocity regions in the mantle and crust are commonly attributed to the presence of silicate melts. Determining melt volume and geometric distribution is fundamental to understanding planetary dynamics. We present a new model for seismic velocity reductions that accounts for the anomalous compressibility of silicate melt, rendering compressional wave velocities more sensitive to melt fraction and distribution than previous estimates. Forward modeling predicts comparable velocity reductions for compressional and shear waves for partially molten mantle, and for low velocity regions associated with the lithosphere-asthenosphere boundary (LAB), melt present at <5% distributed in near-textural equilibrium. These findings reconcile seismic observations for the LAB regionally and locally and favor models of strong coupling across the LAB rather than melt channeling due to shear deformation.
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Affiliation(s)
- Alisha N. Clark
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, CA 95616, USA
- UMR CNRS 7590, Institut de minéralogie et de physique des milieux condensés, Université Pierre-et-Marie-Curie, 75005 Paris, France
- Department of Earth and Planetary Science, Northwestern University, Evanston, IL 60208, USA
| | - Charles E. Lesher
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, CA 95616, USA
- Department of Geoscience, Aarhus University, DK-8000 Aarhus C, Denmark
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24
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Petitgirard S, Malfait WJ, Journaux B, Collings IE, Jennings ES, Blanchard I, Kantor I, Kurnosov A, Cotte M, Dane T, Burghammer M, Rubie DC. SiO_{2} Glass Density to Lower-Mantle Pressures. PHYSICAL REVIEW LETTERS 2017; 119:215701. [PMID: 29219420 DOI: 10.1103/physrevlett.119.215701] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Indexed: 06/07/2023]
Abstract
The convection or settling of matter in the deep Earth's interior is mostly constrained by density variations between the different reservoirs. Knowledge of the density contrast between solid and molten silicates is thus of prime importance to understand and model the dynamic behavior of the past and present Earth. SiO_{2} is the main constituent of Earth's mantle and is the reference model system for the behavior of silicate melts at high pressure. Here, we apply our recently developed x-ray absorption technique to the density of SiO_{2} glass up to 110 GPa, doubling the pressure range for such measurements. Our density data validate recent molecular dynamics simulations and are in good agreement with previous experimental studies conducted at lower pressure. Silica glass rapidly densifies up to 40 GPa, but the density trend then flattens to become asymptotic to the density of SiO_{2} minerals above 60 GPa. The density data present two discontinuities at ∼17 and ∼60 GPa that can be related to a silicon coordination increase from 4 to a mixed 5/6 coordination and from 5/6 to sixfold, respectively. SiO_{2} glass becomes denser than MgSiO_{3} glass at ∼40 GPa, and its density becomes identical to that of MgSiO_{3} glass above 80 GPa. Our results on SiO_{2} glass may suggest that a variation of SiO_{2} content in a basaltic or pyrolitic melt with pressure has at most a minor effect on the final melt density, and iron partitioning between the melts and residual solids is the predominant factor that controls melt buoyancy in the lowermost mantle.
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Affiliation(s)
| | - Wim J Malfait
- Laboratory for Building Energy Materials and Components, Swiss Federal Laboratories for Materials Science and Technology, Empa, 8600 Dübendorf, Switzerland
| | - Baptiste Journaux
- Institut des Géosciences de l'Environnement-UMR 5001, Université Grenoble Alpes CS 40700, 38 058 Grenoble Cedex 9, France
| | - Ines E Collings
- Laboratory of Crystallography, University of Bayreuth, Bayreuth D-95440, Germany
- European Synchrotron Radiation Facility, BP 220, Grenoble F-38043, France
| | - Eleanor S Jennings
- Bayerisches Geoinstitut, University of Bayreuth, Bayreuth D-95440, Germany
| | - Ingrid Blanchard
- Bayerisches Geoinstitut, University of Bayreuth, Bayreuth D-95440, Germany
| | | | - Alexander Kurnosov
- Bayerisches Geoinstitut, University of Bayreuth, Bayreuth D-95440, Germany
| | - Marine Cotte
- European Synchrotron Radiation Facility, BP 220, Grenoble F-38043, France
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 8220, Laboratoire d'archéologie moléculaire et structurale (LAMS), 4 Place Jussieu 75005 Paris, France
| | - Thomas Dane
- European Synchrotron Radiation Facility, BP 220, Grenoble F-38043, France
| | - Manfred Burghammer
- European Synchrotron Radiation Facility, BP 220, Grenoble F-38043, France
| | - David C Rubie
- Bayerisches Geoinstitut, University of Bayreuth, Bayreuth D-95440, Germany
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25
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Electrical conductivity of SiO 2 at extreme conditions and planetary dynamos. Proc Natl Acad Sci U S A 2017; 114:9009-9013. [PMID: 28784773 DOI: 10.1073/pnas.1704762114] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ab intio molecular dynamics simulations show that the electrical conductivity of liquid SiO2 is semimetallic at the conditions of the deep molten mantle of early Earth and super-Earths, raising the possibility of silicate dynamos in these bodies. Whereas the electrical conductivity increases uniformly with increasing temperature, it depends nonmonotonically on compression. At very high pressure, the electrical conductivity decreases on compression, opposite to the behavior of many materials. We show that this behavior is caused by a novel compression mechanism: the development of broken charge ordering, and its influence on the electronic band gap.
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26
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Iron isotopic fractionation between silicate mantle and metallic core at high pressure. Nat Commun 2017; 8:14377. [PMID: 28216664 PMCID: PMC5321738 DOI: 10.1038/ncomms14377] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 12/21/2016] [Indexed: 11/30/2022] Open
Abstract
The +0.1‰ elevated 56Fe/54Fe ratio of terrestrial basalts relative to chondrites was proposed to be a fingerprint of core-mantle segregation. However, the extent of iron isotopic fractionation between molten metal and silicate under high pressure–temperature conditions is poorly known. Here we show that iron forms chemical bonds of similar strengths in basaltic glasses and iron-rich alloys, even at high pressure. From the measured mean force constants of iron bonds, we calculate an equilibrium iron isotope fractionation between silicate and iron under core formation conditions in Earth of ∼0–0.02‰, which is small relative to the +0.1‰ shift of terrestrial basalts. This result is unaffected by small amounts of nickel and candidate core-forming light elements, as the isotopic shifts associated with such alloying are small. This study suggests that the variability in iron isotopic composition in planetary objects cannot be due to core formation. Terrestrial basalts have a unique iron isotopic signature taken as fingerprints of core formation. Here, high pressure studies show that force constants of iron bonds increase with pressure similarly for silicate and metals suggesting interplanetary isotopic variability is not due to core formation.
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27
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Petitgirard S, Spiekermann G, Weis C, Sahle C, Sternemann C, Wilke M. Miniature diamond anvils for X-ray Raman scattering spectroscopy experiments at high pressure. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:276-282. [PMID: 28009567 DOI: 10.1107/s1600577516017112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
X-ray Raman scattering (XRS) spectroscopy is an inelastic scattering method that uses hard X-rays of the order of 10 keV to measure energy-loss spectra at absorption edges of light elements (Si, Mg, O etc.), with an energy resolution below 1 eV. The high-energy X-rays employed with this technique can penetrate thick or dense sample containers such as the diamond anvils employed in high-pressure cells. Here, we describe the use of custom-made conical miniature diamond anvils of less than 500 µm thickness which allow pressure generation of up to 70 GPa. This set-up overcomes the limitations of the XRS technique in very high-pressure measurements (>10 GPa) by drastically improving the signal-to-noise ratio. The conical shape of the base of the diamonds gives a 70° opening angle, enabling measurements in both low- and high-angle scattering geometry. This reduction of the diamond thickness to one-third of the classical diamond anvils considerably lowers the attenuation of the incoming and the scattered beams and thus enhances the signal-to-noise ratio significantly. A further improvement of the signal-to-background ratio is obtained by a recess of ∼20 µm that is milled in the culet of the miniature anvils. This recess increases the sample scattering volume by a factor of three at a pressure of 60 GPa. Examples of X-ray Raman spectra collected at the O K-edge and Si L-edge in SiO2 glass at high pressures up to 47 GPa demonstrate the significant improvement and potential for spectroscopic studies of low-Z elements at high pressure.
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Affiliation(s)
- Sylvain Petitgirard
- University of Bayreuth, Bayerisches Geoinstitut, Universitätsstrasse 30, Bayreuth, 95447, Germany
| | | | - Christopher Weis
- Fakultät Physik / DELTA, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | | | - Christian Sternemann
- Fakultät Physik / DELTA, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Max Wilke
- Universität Potsdam, Potsdam, Germany
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Sahle CJ, Rosa AD, Rossi M, Cerantola V, Spiekermann G, Petitgirard S, Jacobs J, Huotari S, Moretti Sala M, Mirone A. Direct tomography imaging for inelastic X-ray scattering experiments at high pressure. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:269-275. [PMID: 28009566 DOI: 10.1107/s1600577516017100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
A method to separate the non-resonant inelastic X-ray scattering signal of a micro-metric sample contained inside a diamond anvil cell (DAC) from the signal originating from the high-pressure sample environment is described. Especially for high-pressure experiments, the parasitic signal originating from the diamond anvils, the gasket and/or the pressure medium can easily obscure the sample signal or even render the experiment impossible. Another severe complication for high-pressure non-resonant inelastic X-ray measurements, such as X-ray Raman scattering spectroscopy, can be the proximity of the desired sample edge energy to an absorption edge energy of elements constituting the DAC. It is shown that recording the scattered signal in a spatially resolved manner allows these problems to be overcome by separating the sample signal from the spurious scattering of the DAC without constraints on the solid angle of detection. Furthermore, simple machine learning algorithms facilitate finding the corresponding detector pixels that record the sample signal. The outlined experimental technique and data analysis approach are demonstrated by presenting spectra of the Si L2,3-edge and O K-edge of compressed α-quartz. The spectra are of unprecedented quality and both the O K-edge and the Si L2,3-edge clearly show the existence of a pressure-induced phase transition between 10 and 24 GPa.
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Affiliation(s)
- Ch J Sahle
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - A D Rosa
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - M Rossi
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - V Cerantola
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - G Spiekermann
- Institute of Earth and Environmental Science, Universität Potsdam, Potsdam, Germany
| | - S Petitgirard
- Bayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany
| | - J Jacobs
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - S Huotari
- Department of Physics, POB 64, FI-00014, University of Helsinki, Helsinki, Finland
| | - M Moretti Sala
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - A Mirone
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
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29
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Ghosh DB, Karki BB. Solid-liquid density and spin crossovers in (Mg, Fe)O system at deep mantle conditions. Sci Rep 2016; 6:37269. [PMID: 27872491 PMCID: PMC5118715 DOI: 10.1038/srep37269] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 10/27/2016] [Indexed: 11/08/2022] Open
Abstract
The low/ultralow-velocity zones in the Earth's mantle can be explained by the presence of partial melting, critically depending on density contrast between the melt and surrounding solid mantle. Here, first-principles molecular dynamics simulations of (Mg, Fe) O ferropericlase in the solid and liquid states show that their densities increasingly approach each other as pressure increases. The isochemical density difference between them diminishes from 0.78 (±0.7) g/cm3 at zero pressure (3000 K) to 0.16 (±0.04) g/cm3 at 135 GPa (4000 K) for pure and alloyed compositions containing up to 25% iron. The simulations also predict a high-spin to low-spin transition of iron in the liquid ferropericlase gradually occurring over a pressure interval centered at 55 GPa (4000 K) accompanied by a density increase of 0.14 (±0.02) g/cm3. Temperature tends to widen the transition to higher pressure. The estimated iron partition coefficient between the solid and liquid ferropericlase varies from 0.3 to 0.6 over the pressure range of 23 to 135 GPa. Based on these results, an excess of as low as 5% iron dissolved in the liquid could cause the solid-liquid density crossover at conditions of the lowermost mantle.
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Affiliation(s)
- Dipta B. Ghosh
- School of Electrical Engineering and Computer Science, Louisiana State University, Baton Rouge, LA 70803
| | - Bijaya B. Karki
- School of Electrical Engineering and Computer Science, Louisiana State University, Baton Rouge, LA 70803
- Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803
- Center for Computation and Technology, Louisiana State University, Baton Rouge, LA 70803
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Abstract
One key for understanding the stratification in the deep mantle lies in the determination of the density and structure of matter at high pressures, as well as the density contrast between solid and liquid silicate phases. Indeed, the density contrast is the main control on the entrainment or settlement of matter and is of fundamental importance for understanding the past and present dynamic behavior of the deepest part of the Earth's mantle. Here, we adapted the X-ray absorption method to the small dimensions of the diamond anvil cell, enabling density measurements of amorphous materials to unprecedented conditions of pressure. Our density data for MgSiO3 glass up to 127 GPa are considerably higher than those previously derived from Brillouin spectroscopy but validate recent ab initio molecular dynamics simulations. A fourth-order Birch-Murnaghan equation of state reproduces our experimental data over the entire pressure regime of the mantle. At the core-mantle boundary (CMB) pressure, the density of MgSiO3 glass is 5.48 ± 0.18 g/cm(3), which is only 1.6% lower than that of MgSiO3 bridgmanite at 5.57 g/cm(3), i.e., they are the same within the uncertainty. Taking into account the partitioning of iron into the melt, we conclude that melts are denser than the surrounding solid phases in the lowermost mantle and that melts will be trapped above the CMB.
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Smedskjaer MM, Bauchy M, Mauro JC, Rzoska SJ, Bockowski M. Unique effects of thermal and pressure histories on glass hardness: Structural and topological origin. J Chem Phys 2015; 143:164505. [DOI: 10.1063/1.4934540] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Morten M. Smedskjaer
- Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark
| | - Mathieu Bauchy
- Department of Civil and Environmental Engineering, University of California, Los Angeles, California 90095, USA
| | - John C. Mauro
- Science and Technology Division, Corning Incorporated, Corning, New York 14831, USA
| | - Sylwester J. Rzoska
- Institute of High Pressure Physics, Polish Academy of Sciences, Warsaw 01-142, Poland
- Institute of Physics, University of Silesia, Chorzow 41-500, Poland
| | - Michal Bockowski
- Institute of High Pressure Physics, Polish Academy of Sciences, Warsaw 01-142, Poland
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32
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Bajgain S, Ghosh DB, Karki BB. Structure and density of basaltic melts at mantle conditions from first-principles simulations. Nat Commun 2015; 6:8578. [PMID: 26450568 PMCID: PMC4633951 DOI: 10.1038/ncomms9578] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 09/06/2015] [Indexed: 11/11/2022] Open
Abstract
The origin and stability of deep-mantle melts, and the magmatic processes at different times of Earth's history are controlled by the physical properties of constituent silicate liquids. Here we report density functional theory-based simulations of model basalt, hydrous model basalt and near-MORB to assess the effects of iron and water on the melt structure and density, respectively. Our results suggest that as pressure increases, all types of coordination between major cations and anions strongly increase, and the water speciation changes from isolated species to extended forms. These structural changes are responsible for rapid initial melt densification on compression thereby making these basaltic melts possibly buoyantly stable at one or more depths. Our finding that the melt-water system is ideal (nearly zero volume of mixing) and miscible (negative enthalpy of mixing) over most of the mantle conditions strengthens the idea of potential water enrichment of deep-mantle melts and early magma ocean.
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Affiliation(s)
- Suraj Bajgain
- Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Dipta B. Ghosh
- School of Electrical Engineering and Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Bijaya B. Karki
- Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA
- School of Electrical Engineering and Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803, USA
- Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Liermann HP, Konôpková Z, Morgenroth W, Glazyrin K, Bednarčik J, McBride EE, Petitgirard S, Delitz JT, Wendt M, Bican Y, Ehnes A, Schwark I, Rothkirch A, Tischer M, Heuer J, Schulte-Schrepping H, Kracht T, Franz H. The Extreme Conditions Beamline P02.2 and the Extreme Conditions Science Infrastructure at PETRA III. JOURNAL OF SYNCHROTRON RADIATION 2015; 22:908-24. [PMID: 26134794 PMCID: PMC4489534 DOI: 10.1107/s1600577515005937] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 03/24/2015] [Indexed: 05/18/2023]
Abstract
A detailed description is presented of the Extreme Conditions Beamline P02.2 for micro X-ray diffraction studies of matter at simultaneous high pressure and high/low temperatures at PETRA III, in Hamburg, Germany. This includes performance of the X-ray optics and instrumental resolution as well as an overview of the different sample environments available for high-pressure studies in the diamond anvil cell. Particularly emphasized are the high-brilliance and high-energy X-ray diffraction capabilities of the beamline in conjunction with the use of fast area detectors to conduct time-resolved compression studies in the millisecond time regime. Finally, the current capability of the Extreme Conditions Science Infrastructure to support high-pressure research at the Extreme Conditions Beamline and other PETRA III beamlines is described.
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Affiliation(s)
- H.-P. Liermann
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
- Correspondence e-mail:
| | - Z. Konôpková
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - W. Morgenroth
- Department of Crystallography, University of Frankfurt, Frankfurt, Germany
| | - K. Glazyrin
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - J. Bednarčik
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - E. E. McBride
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - S. Petitgirard
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
- Bayrisches Geoinstitut, University of Bayreuth, Bayreuth, Germany
| | - J. T. Delitz
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - M. Wendt
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Y. Bican
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - A. Ehnes
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - I. Schwark
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - A. Rothkirch
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - M. Tischer
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - J. Heuer
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | | | - T. Kracht
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - H. Franz
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
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34
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Salmon PS, Zeidler A. Networks under pressure: the development of in situ high-pressure neutron diffraction for glassy and liquid materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:133201. [PMID: 25743915 DOI: 10.1088/0953-8984/27/13/133201] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The pressure-driven collapse in the structure of network-forming materials will be considered in the gigapascal (GPa) regime, where the development of in situ high-pressure neutron diffraction has enabled this technique to obtain new structural information. The improvements to the neutron diffraction methodology are discussed, and the complementary nature of the results is illustrated by considering the pressure-driven structural transformations for several key network-forming materials that have also been investigated by using other experimental techniques such as x-ray diffraction, inelastic x-ray scattering, x-ray absorption spectroscopy and Raman spectroscopy. A starting point is provided by the pressure-driven network collapse of the prototypical network-forming oxide glasses B2O3, SiO2 and GeO2. Here, the combined results help to show that the coordination number of network-forming structural motifs in a wide range of glassy and liquid oxide materials can be rationalised in terms of the oxygen-packing fraction over an extensive pressure and temperature range. The pressure-driven network collapse of the prototypical chalcogenide glass GeSe2 is also considered where, as for the case of glassy GeO2, site-specific structural information is now available from the method of in situ high-pressure neutron diffraction with isotope substitution. The application of in situ high-pressure neutron diffraction to other structurally disordered network-forming materials is also summarised. In all of this work a key theme concerns the rich diversity in the mechanisms of network collapse, which drive the changes in physico-chemical properties of these materials. A more complete picture of the mechanisms is provided by molecular dynamics simulations using theoretical schemes that give a good account of the experimental results.
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35
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Drewitt JWE, Jahn S, Sanloup C, de Grouchy C, Garbarino G, Hennet L. Development of chemical and topological structure in aluminosilicate liquids and glasses at high pressure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:105103. [PMID: 25662518 DOI: 10.1088/0953-8984/27/10/105103] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The high pressure structure of liquid and glassy anorthite (CaAl(2)Si(2)O(8)) and calcium aluminate (CaAl(2)O(4)) glass was measured by using in situ synchrotron x-ray diffraction in a diamond anvil cell up to 32.4(2) GPa. The results, combined with ab initio molecular dynamics and classical molecular dynamics simulations using a polarizable ion model, reveal a continuous increase in Al coordination by oxygen, with 5-fold coordinated Al dominating at 15 GPa and a preponderance of 6-fold coordinated Al at higher pressures. The development of a peak in the measured total structure factors at 3.1 Å(-1) is interpreted as a signature of changes in topological order. During compression, cation-centred polyhedra develop edge- and face- sharing networks. Above 10 GPa, following the pressure-induced breakdown of the network structure, the anions adopt a structure similar to a random close packing of hard spheres.
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Affiliation(s)
- James W E Drewitt
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, UK. Centre for Science at Extreme Conditions, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3JZ, UK
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36
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Murakami M, Goncharov AF, Hirao N, Masuda R, Mitsui T, Thomas SM, Bina CR. High-pressure radiative conductivity of dense silicate glasses with potential implications for dark magmas. Nat Commun 2014; 5:5428. [DOI: 10.1038/ncomms6428] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 10/01/2014] [Indexed: 11/09/2022] Open
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37
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Zeidler A, Wezka K, Rowlands RF, Whittaker DAJ, Salmon PS, Polidori A, Drewitt JWE, Klotz S, Fischer HE, Wilding MC, Bull CL, Tucker MG, Wilson M. High-pressure transformation of SiO₂ glass from a tetrahedral to an octahedral network: a joint approach using neutron diffraction and molecular dynamics. PHYSICAL REVIEW LETTERS 2014; 113:135501. [PMID: 25302900 DOI: 10.1103/physrevlett.113.135501] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Indexed: 06/04/2023]
Abstract
A combination of in situ high-pressure neutron diffraction at pressures up to 17.5(5) GPa and molecular dynamics simulations employing a many-body interatomic potential model is used to investigate the structure of cold-compressed silica glass. The simulations give a good account of the neutron diffraction results and of existing x-ray diffraction results at pressures up to ~60 GPa. On the basis of the molecular dynamics results, an atomistic model for densification is proposed in which rings are "zipped" by a pairing of five- and/or sixfold coordinated Si sites. The model gives an accurate description for the dependence of the mean primitive ring size ⟨n⟩ on the mean Si-O coordination number, thereby linking a parameter that is sensitive to ordering on multiple length scales to a readily measurable parameter that describes the local coordination environment.
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Affiliation(s)
- Anita Zeidler
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | - Kamil Wezka
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | - Ruth F Rowlands
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | | | - Philip S Salmon
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | - Annalisa Polidori
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | - James W E Drewitt
- Centre for Science at Extreme Conditions, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - Stefan Klotz
- IMPMC, CNRS UMR 7590, Université Pierre et Marie Curie, 75252 Paris, France
| | - Henry E Fischer
- Institut Laue Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble, France
| | - Martin C Wilding
- IMPS, Aberystwyth University, Aberystwyth SY23 3BZ, United Kingdom
| | - Craig L Bull
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom
| | - Matthew G Tucker
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom
| | - Mark Wilson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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38
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McMahon MI. High-pressure X-ray science on the ultimate storage ring. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:1077-1083. [PMID: 25177996 DOI: 10.1107/s1600577514012855] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/02/2014] [Indexed: 06/03/2023]
Abstract
The advent of the ESRF, APS and SPring-8 third-generation synchrotron sources in the mid-1990s heralded a golden age of high-pressure X-ray science. The high-energy monochromatic micro-focused X-ray beams from these storage rings, combined with the new high-pressure diffraction and spectroscopy techniques developed in the late 1980s, meant that researchers were immediately able to make detailed structural studies at pressures comparable with those at the centre of the Earth, studies that were simply not possible only five years previously. And new techniques, such as X-ray inelastic scattering and X-ray nuclear scattering, became possible at high pressure for the first time, providing wholly-new insight into the behaviour of materials at high densities. The arrival of new diffraction-limited storage rings, with their much greater brightness, and ability to achieve focal-spot diameters for high-energy X-ray beams of below 1 µm, offers the possibility of a new generation of high-pressure science, both extending the scope of what is already possible, and also opening ways to wholly-new areas of investigation.
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Affiliation(s)
- Malcolm I McMahon
- SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh, UK
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39
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Packing and the structural transformations in liquid and amorphous oxides from ambient to extreme conditions. Proc Natl Acad Sci U S A 2014; 111:10045-8. [PMID: 24982151 DOI: 10.1073/pnas.1405660111] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Liquid and glassy oxide materials play a vital role in multiple scientific and technological disciplines, but little is known about the part played by oxygen-oxygen interactions in the structural transformations that change their physical properties. Here we show that the coordination number of network-forming structural motifs, which play a key role in defining the topological ordering, can be rationalized in terms of the oxygen-packing fraction over an extensive pressure and temperature range. The result is a structural map for predicting the likely regimes of topological change for a range of oxide materials. This information can be used to forecast when changes may occur to the transport properties and compressibility of, e.g., fluids in planetary interiors, and is a prerequisite for the preparation of new materials following the principles of rational design.
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